Image inspection device

ABSTRACT

An image inspection device has a first suction conveyance unit which is arranged on the upstream side with a conveyance surface as an upper surface, a second suction conveyance unit which is arranged on the downstream side with a conveyance surface as a lower surface to make the conveyance surface continuous from the upstream side, a first inspection section which inspects an image on a front surface of an inspection object which is conveyed to the first suction conveyance unit and a second inspection section which inspects an image on a back surface of the inspection object which is conveyed to the second suction conveyance unit. The inspection object is conveyed in a state of being sucked and held on the first and second suction conveyance units and therefore is stable in position and posture in conveyance and an expected accuracy is maintained in inspection performed by the first and second inspection sections.

TECHNICAL FIELD

The present invention concerns an image inspection device which inspectsimages which are formed on a sheet-shaped inspection object andparticularly relates to the image inspection device which is able toinspect the images which are formed on both front and back surfaces ofthe inspection object with high accuracy while conveying the inspectionobject in one direction without inverting the inspection object.

BACKGROUND ART

In an image forming apparatus which is equipped with a function offorming the images on both the front and back surfaces of a sheet, thereare cases where it becomes necessary to inspect the images on both thefront and back surfaces of the sheet while conveying the sheet. In sucha case, it is possible to adopt such a configuration that one camerawhich captures the images formed on the sheet and one sensor areinstalled, an inverting section is installed on a path along which thesheet is conveyed, the image on the front surface is inspected by thesensor and thereafter the sheet is inverted so as to again pass underthe sensor again and the image on the back surface of the sheet isinspected. However, a method of conveying and inverting the sheet by theinverting section in this way has such a problem that a mechanism iscomplicated and is increased in size.

An invention of an image forming apparatus is disclosed in PatentLiterature 1. The image forming apparatus is equipped with a jamrecovery device and is of the type that in a case where the top sheetwhich is jammed is located on the downstream side of a sheet inspectiondevice 150, printing is resumed from images which are formed on the topjammed sheet on condition that an instruction to resume printing isissued from a user.

The image forming apparatus has a camera unit 230. Then, a sheetconveyance path 223 along which the sheet is conveyed in one directionfrom the upstream to the downstream is installed on the camera unit 230and two cameras 231 and 232 are arranged at vertically aligned positionsabove and under the path 223 so as to face each other. That is, unlikethe configuration that the images on both the front and back surfaces ofone sheet are inspected by using one camera and the inverting section onthe conveyance path, in the camera unit 230, the sheet is conveyed inone direction without being inverted and the two cameras 231 and 232read out the respective images on upper and lower surfaces (the frontand back surfaces) of the conveyed sheet respectively while the sheet isbeing conveyed. The sheet inspection device 150 inspects the imageswhich are printed on the sheet by using captured images on the sheetwhich are sent from the camera unit 230.

Patent Literature 1: Japanese Unexamined Patent Application PublicationNo. 2018-31963

SUMMARY OF INVENTION Technical Problem

In the camera unit of the image forming apparatus which is disclosed inPatent Literature 1, the two cameras are arranged at the verticallyaligned positions with the sheet conveyance path being sandwichedbetween the two cameras so as to face each other and the camera unit isconfigured that images on vertically aligned places on both the frontand back surfaces of the sheet are captured by the two cameras.Therefore, at positions on the sheet conveyance path where the camerasare installed, it is necessary to expose both the front and backsurfaces of the sheet relative to the cameras across sufficiently wideareas. However, when large openings are formed in both upper and lowersurfaces of a section of the sheet conveyance path where the cameras arearranged in order to bring both the front and back surfaces of theconveyed sheet into largely exposed states, guidance and holding of thesheet which is conveyed are not sufficiently conducted and the positionof the sheet fluctuates while the sheet is being conveyed. Therefore,there is a problem of the possibility that an image capturing accuracyby the camera may be lowered.

The present invention has been made in view of such related art and anissue thereof and aims to provide an image inspection device which isable to inspect images on both front and back surfaces of a sheet-shapedinspection object while the sheet-shaped inspection object is beingstably conveyed in one direction with no need of using a complicatedmechanism which inverts the sheet-shaped inspection object.

Solution to Problem

An image inspection device according to a first aspect of the presentinvention includes a first conveyance unit which is arranged in such amanner that a conveyance surface on which a sheet-shaped inspectionobject is conveyed is located on an upper surface side, a secondconveyance unit which is arranged adjacent to the conveyance surface ofthe first conveyance unit along a conveyance object conveyance directionin such a manner that a conveyance surface on which the sheet-shapedinspection object is conveyed is located on a lower surface side, afirst inspection section which inspects an image on a front surface ofthe inspection object which is conveyed by the first conveyance unit,and a second inspection section which inspects an image on a backsurface of the inspection object which is conveyed by the secondconveyance unit.

Advantageous Effects of Invention

According to the image inspection device according to the first aspectof the present invention, the inspection object is stably conveyed bybeing held on the upper surface side of the first conveyance unit, forexample, by suction and bonding, is stably conveyed by being held on thelower surface side of the second conveyance unit, and delivery of theinspection object between the first conveyance unit and the secondconveyance unit is stably performed. Consequently, since the positionand the posture of the inspection object which is being conveyed arestabilized, an expected accuracy is maintained in inspection by thefirst inspection section and the second inspection section.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an overall configuration diagram illustrating one example ofan image forming system which includes an image inspection deviceaccording to one embodiment of the present invention;

FIG. 2 is a schematic configuration diagram illustrating one example ofthe image inspection device according to the embodiment of the presentinvention;

FIG. 3 is a schematic configuration diagram illustrating one example ofthe image inspection device which is illustrated by further addingsupport sections for inspection sections to the schematic configurationdiagram in FIG. 2;

FIG. 4 is a front view illustrating one example of the image inspectiondevice according to the embodiment of the present invention;

FIG. 5 is a perspective view illustrating one example of the imageinspection device according to the embodiment when seen diagonally fromabove;

FIG. 6 is a perspective view illustrating one example of the imageinspection device according to the embodiment when seen diagonally frombelow;

FIG. 7 is a perspective view illustrating one example of upstream-sidesuction conveyance unit, inspection section and so forth of the imageinspection device according to the embodiment of the present inventionwhen seen diagonally from above;

FIG. 8 is a perspective view illustrating one example of the suctionconveyance unit and the inspection section of the image inspectiondevice according to the embodiment of the present invention when seendiagonally from below;

FIG. 9 is a perspective view illustrating one example of upstream sideholding section and inspection section of the image inspection deviceaccording to the embodiment of the present invention when seendiagonally from below;

FIG. 10 is an exploded hierarchical perspective view illustrating oneexample of the upstream side holding section and suction conveyance unitof the image inspection device according to the embodiment of thepresent invention when seen diagonally from above;

FIG. 11 is a schematic perspective view illustrating one example of aconveyance direction adjustment element which adjusts the conveyancedirection that the suction conveyance unit conveys the inspection objectto the inspection section in the image inspection device according tothe embodiment of the present invention;

FIG. 12 a schematic plan view illustrating one example of the conveyancedirection adjustment element which adjusts the conveyance direction thatthe suction conveyance unit conveys the inspection object to theinspection section in the image inspection device according to theembodiment of the present invention;

FIG. 13 is a schematic front view illustrating a first modified exampleof the image inspection device according to the embodiment of thepresent invention;

FIG. 14 is a schematic front view illustrating a second modified exampleof the image inspection device according to the embodiment of thepresent invention;

FIG. 15 is a schematic front view illustrating a third modified exampleof the image inspection device according to the embodiment of thepresent invention;

FIG. 16 is a schematic front view illustrating a fourth modified exampleof the image inspection device according to the embodiment of thepresent invention;

FIG. 17 is a schematic front view illustrating a fifth modified exampleof the image inspection device according to the embodiment of thepresent invention;

FIG. 18 is a schematic front view illustrating a sixth modified exampleof the image inspection device according to the embodiment of thepresent invention;

FIG. 19 is a perspective view illustrating one example of theupstream-side suction conveyance unit, inspection section and so forthwhen seen diagonally from above in a seventh modified example of theimage inspection device according to the embodiment of the presentinvention; and

FIG. 20 is a schematic configuration diagram illustrating an eightmodified example of the image inspection device according to theembodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

<<Basic Structure and Configuration of Image Forming System>>

One embodiment of the present invention will be described with referenceto FIG. 1 to FIG. 12.

As schematically illustrated in FIG. 1 by simplifying the structure, oneembodiment of the present invention relates to an image forming systemwhich includes a printing device 100, an image inspection device 200 anda post-processing device 300 and particularly has characteristics in thestructure of the image inspection device 200 as will be described later.

The printing device 100 has a plurality of inkjet heads 101 which aredifferent from one another in ink color, a conveyance path 102 alongwhich a sheet-shaped medium (a printing sheet) which is an inspectionobject of the image inspection device 200 is conveyed, and a suctionconveyance unit 103 which is installed directly under the inkjet heads101 in a state of being connected with the conveyance path 102.Illustration of other configurations such as a printing sheet feedingelement and so forth is omitted. The post-processing device 300 is adevice which performs various post-processing operations on the printingsheet on which images are printed by the printing device 100 and theimages so printed are inspected by the image inspection device 200 andthen discharges the printing sheet. As contents of the post-processing,sorting work such as sorting, stacking and so forth, stapling, paperinsertion, paper folding of various forms, insertion of the paper intoan envelope and so forth are included, and it is possible to install thepost-processing device 300 which is equipped with necessary functions inaccordance with a purpose.

<<Basic Structure and Configuration of Image Inspection Device>>

First, a basic configuration of the image inspection device 200 will bedescribed with reference to FIG. 2 and FIG. 3.

The image inspection device 200 has two suction conveyance units (afirst suction conveyance unit 1 and a second suction conveyance unit 2)as elements for conveying a sheet-shaped inspection object (asheet-shaped medium, that is, the printing paper). First, the firstsuction conveyance unit 1 will be briefly described within a range whichis illustrated in FIG. 2. The first suction conveyance unit 1 has a beltconveyor that a conveyor belt 6 is wound around an upstream-side driveroller 3, an upstream-side driven roller 4, and other two small drivenrollers 5. As will be illustrated later in other drawings (for example,see FIG. 5), a resinous intermediate plate 7 is in contact with a lowersurface of the upper-side conveyor belt 6 of the first suctionconveyance unit 1 and a platen 8 which is a plate material is in contactwith a lower surface of the intermediate plate 7. Many through-holes areformed in the conveyor belt 6, the intermediate plate 7, and the platen8 respectively. Further, a chamber (not illustrated) is attached to alower surface of the platen 8 and air is sucked by a fan (notillustrated) which is attached to a lower part of the chamber so as tomaintain a negative pressure in the chamber. Accordingly, when the fanis driven, the air is sucked into the chamber from the top of theconveyor belt 6 into the chamber through the respective through-holes inthe conveyor belt 6, the intermediate plate 7, and the platen 8 andthereby the inspection object is sucked onto the conveyance surface ofthe conveyor belt 6. Then, when the conveyor belt 6 is driven, itbecomes possible to convey the inspection object.

Incidentally, the aforementioned upstream side and downstream side areused in the sense of the upstream side and the downstream side of adirection that the inspection object is conveyed by the suctionconveyance units 1 and 2, and the same also applies to the followingdescription.

In the first and second suction conveyance units 1 and 2 of the imageinspection device 200, a sheet which is a sheet-shaped medium such asprinting paper and so forth is conveyed as an object to be conveyed.Unlike a bag and so forth having a structure that two sheets arestacked, the sheet is sucked to the conveyor belt 6 across the entiresurface, a position of the sheet which is vertical to the conveyor belt6 is fixed within the conveyance surface, and the sheet is conveyed withmovement of the conveyor belt 6 in a stable state. Therefore, aheight-wise position of the sheet which is conveyed does not fluctuateand a position accuracy of the sheet is high. Accordingly, in a casewhere a CIS (Contact Image Sensor) and so forth which are shallower thana camera and so forth in depth of field and for which a high arrangementaccuracy is required for obtaining an expected reading accuracy isadopted as an element for inspecting the sheet which is conveyed by thefirst and second suction conveyance units 1 and 2 are adopted, itbecomes possible to sufficiently exhibit the high reading accuracy thatthe CIS originally has. The camera and CIS will be described later.

As illustrated in FIG. 2, in an inspection object conveyance directionwhich directs from left to right in the drawing, the conveyance unitwhich is located on the upstream side is the first suction conveyanceunit 1 and the conveyance unit which is located on the downstream sideis the second suction conveyance unit 2. Although the first suctionconveyance unit 1 and the second suction conveyance unit 2 have the samefunctional configuration, the first suction conveyance unit 1 isarranged horizontally in such a manner that the conveyance surface ontowhich the inspection object is sucked and conveyed is located on theupper surface side. Accordingly, the inspection object which is conveyedby the first suction conveyance unit 1 is conveyed with its frontsurface facing upward. On the other hand, the second suction conveyanceunit 2 is arranged in a state of being turned upside down relative tothe first suction conveyance unit 1. That is, the second suctionconveyance unit 2 is horizontally arranged in such a manner that theconveyance surface onto which the inspection object is sucked andconveyed is located on the lower surface side. Accordingly, theinspection object which is conveyed by the second suction conveyanceunit 2 is conveyed with its back surface facing downward. The firstsuction conveyance unit 1 and the second suction conveyance unit 2 arearranged adjacent to each other in such a manner that the respectiveconveyance surfaces almost match each other and are able to continuouslyconvey the inspection object along one horizontal conveyance path.

As illustrated in FIG. 2, the image inspection device 200 has twoinspection sections (a first inspection section 11 and a secondinspection section 12) as elements for inspecting images on theinspection object. The first inspection section 11 is installed above anupstream-side end of the first suction conveyance unit 1 in a state ofbeing directed downward so as to face the conveyor belt 6. The secondinspection section 12 is installed under an upstream-side end of thesecond suction conveyance unit 2 in a state of being directed upward soas to face the conveyor belt 6. The first inspection section 11 and thesecond inspection section 12 are configured by the CISs (Contact ImageSensor) which are the same as each other in specification. However,sensors which are based on other principles or have other structures andconfigurations are not limited to the CISs as the inspection sectionswhich read out images which are formed on the inspection object forinspection, and cameras may also be used as will be described later.

As illustrated in FIG. 2, the image inspection device 200 includes anintroduction guide plate 13 which is adjacent to the upstream-side endof the first suction conveyance unit 1 and guides the inspection objectwhich is sent from the upstream-side printing device 100 to theconveyance surface.

In addition, a press roller 14 which presses floating of a top edge ofthe inspection object which is introduced by being guided by theintroduction guide plate 13 is installed above the driven roller 4 ofthe first suction conveyance unit 1. The press roller 14 rotatesfollowing the conveyor belt 6.

As illustrated in FIG. 2, the image inspection device 200 includes anintermediate guide plate 15 which is installed between the first suctionconveyance unit 1 and the second suction conveyance unit 2 and guidesthe inspection object sent from the first suction conveyance unit 1 tothe conveyance surface of the second suction conveyance unit 2. Inaddition, a hanging prevention roller 16 is installed under the drivenroller 4 of the second suction conveyance unit 2 as a hanging preventionmember which prevents the top edge of the inspection object which isintroduced by being guided by the intermediate guide plate 15 fromhanging as will be described later with reference to other drawings(see, for example, FIG. 6 and FIG. 8).

As illustrated in FIG. 2, the image inspection device 200 includes adischarge guide plate 17 which is adjacent to a downstream-side end ofthe second suction conveyance unit 2 and discharges the inspectionobject which is conveyed by the second suction conveyance unit 2.

Next, a basic configuration of the image inspection device 200 which isnot illustrated in FIG. 2 will be described with reference to FIG. 3.The aforementioned first inspection section 11 and second inspectionsection 12 are respectively attached to a first support section 21 and asecond support section 22 which are positioned relative to the firstsuction conveyance unit 1 and the second suction conveyance unit 2respectively. Although the first support section 21 and the secondsupport section 22 have substantially the same functional configuration,the first support section 21 and the second support section 22 arearranged in a state of being mutually turned upside down so as to facethe respective conveyance surfaces of the first suction conveyance unit1 and the second suction conveyance unit 2 which are arranged in a stateof being mutually turned upside down. In addition, as will be describedlater with reference to other drawings (see, for example, FIG. 5 and soforth), the first support section 21 and the second support section 22are supported to a frame (not illustrated) of the image inspectiondevice 200 to be rotationally movable around support points A and Brespectively at both ends of a long support shaft 23. In FIG. 3, acentral axis of the long support shaft 23 is vertical to a surface ofpaper and the first support section 21 and the second support section 22are supported to the frame in a state of being rotationally movable inboth left and right directions around this central axis (described laterwith reference to arrows indicated in FIG. 5). In addition, the firstsupport section 21 and the second support section 22 are supported tothe frame (not illustrated) of the image inspection device 200 to berotationally movable around a support point C by a short support shaft24 respectively. In FIG. 3, a central axis of the short support shaft 24is parallel with the surface of paper and almost horizontal and thefirst support section 21 and the second support section 22 are supportedto the frame in a state of being rotationally movable around the centralaxis of the short support shaft 24 in both paper surface forwarddirection and paper surface rearward direction (described later withreference to the arrows indicated in FIG. 5). Although details will bedescribed later, supported states of the first support section 21 andthe second support section 22 at the support points A, B and C are notfixed and the image inspection device 200 is configured that even in acase where the frame is deformed by addition of external force, thefirst support section 21 and the second support section 22 are notdeformed and no harmful change occurs in an arrangement relation of theboth because the first support section 21 and the second support section22 are made rotationally movable in the abovementioned two directions.

According to the image inspection device 200 in the embodiment havingthe above-described basic configuration, the inspection object is stablyconveyed in a state of being sucked and held on the conveyance surfacewhich is located on the upper surface side of the first suctionconveyance unit 1 and then is delivered to the second suction conveyanceunit 2 and is stably conveyed in a state of being sucked and held on theconveyance surface which is located on the lower surface side of thesecond suction conveyance unit 2. Since the inspection object isconveyed in a sucked state in this way, the position and the posture ofthe inspection object do not become unstable while the inspection objectis being conveyed and thereby it becomes possible to inspect the imageson both the front and back surfaces of the inspection object withnecessary accuracy by the two inspection sections 11 and 12 while stablyconveying the inspection object in one direction without using acomplicated mechanism which inverts the inspection object.

In addition, according to the image inspection device 200, since therespective inspection sections 11 and 12 are arranged in the vicinity ofthe upstream-side ends of the respective suction conveyance units 1 and2, most parts of the conveyance surfaces of the respective suctionconveyance units 1 and 2 are in open states and there is no obstacle onthe conveyance surfaces. Therefore, a manager who manages the imageinspection device 200 or a worker who performs maintenance and so forthof the image inspection device 200 is able to access to the conveyancesurfaces of the respective suction conveyance units 1 and 2 with ease.Accordingly, since the conveyance path 102 of the inspection object isnot sandwiched between the inspection sections unlike the camera unit ofthe image forming apparatus which is disclosed in Patent Literature 1which is described in (Background Art), even when a jam occurs in theinspection object which is being conveyed, the manager or the worker isable to remove the jammed inspection object by inserting his/her handinto a trouble-occurred place with ease.

In addition, according to the image inspection device 200, since therespective inspection sections 11 and 12 are arranged in the vicinity ofthe upstream-side ends of the respective suction conveyance units 1 and2, in a case where results of image detection by the inspection sections11 and 12 are utilized on the downstream side, it is preferable toarrange the inspection sections in the vicinity of the upstream sideends of the suction conveyance units because sufficient time is secured.For example, in a case where an inspection object which is decided to beunfavorable in inspection result is sorted as a defective product in thepost-processing device 300 which is located at the rear stage of theimage inspection device 200, it is desirable to obtain information fromthe inspection sections 11 and 12 as soon as possible for decision ofwhether the inspection object is the defective product. According to theimage inspection device 200 of the present embodiment, since theinspection sections 11 and 12 are installed on the upstream sides of thefirst and second suction conveyance units 1 and 2 respectively, itbecomes possible for a control unit to obtain the inspection resultsearlier than a case where the inspection sections are installed on thedownstream sides and to execute the necessary post-processing withoutdelay.

<<Details of Structure of Image Inspection Device>>

Next, a concrete structure of the image inspection device 200 which hasthe above-described basic structure described with reference to FIG. 4to FIG. 12. First, the first support section 21 and the second supportsection 22 to which the first inspection section 11 and the secondinspection section 12 are attached respectively and a structure and soforth that the respective first and second support sections 21 and 22are positioned relative to the first and second suction conveyance units1 and 2 respectively will be described with reference to FIG. 4 to FIG.9.

As illustrated particularly in FIG. 5 and FIG. 9, the first supportsection 21 is a frame body having an almost square outer shape whichalmost matches a planar shape of the first suction conveyance unit 1. Infour walls of the first support section 21, the first inspection section11 which sets a direction (a width direction of the inspection object)orthogonal to the inspection object conveyance direction as alongitudinal direction is attached to the inner side of an upstream-sidewall which is orthogonal to the inspection object conveyance direction.An inspection element of the first inspection section 11 is directed toa direction of the conveyor belt 6.

As illustrated particularly in FIG. 9, support legs 25 which are set topredetermined dimensions are formed on four corners of the first supportsection 21 so as to project toward the side which faces the firstsuction conveyance unit 1. A groove 26 is vertically formed in eachsupport leg 25. As illustrated particularly in FIG. 4 and FIG. 5, thefour support legs 25 of the first support section 21 abut on the uppersurface of the platen 8 which protrudes from the intermediate plate 7 ofthe first suction conveyance unit 1 at every two positions (fourpositions in total) with the conveyor belt 6 being sandwichedtherebetween. Then, the first support section 21 holds the first suctionconveyance unit 1 by pressing the first suction conveyance unit 1against the support legs 25 and thereby maintains a distance between thefirst inspection section 11 and the conveyance surface of the firstsuction conveyance unit 1 constant as will be described in the followingand as indicated by a distance D particularly in FIG. 4.

As illustrated particularly in FIG. 4, FIG. 5 and FIG. 7, first, awinding shaft 27 is installed on one wall of the first support section21 which is parallel with the inspection object conveyance direction onthe opposite side of the first suction conveyance unit 1 in parallelwith the inspection object conveyance direction. As illustratedparticularly in FIG. 5 and FIG. 7, every two pulleys 28 a and 28 b areinstalled on both ends of the winding shaft 27. In addition, pulleys 29and 29 are installed respectively on two corners of the other wall ofthe first support section 21 which is parallel with the inspectionobject conveyance direction on the opposite side of the first suctionconveyance unit 1. A suspension wire 30 is wound around the pulleys 28 aand 28 b of the winding shaft 27 with its base end being coupledthereto. Two suspension wires 30 and 30 of the outer two pulleys 28 aand 28 a in every two pulleys on the both ends of the winding shaft 27are led out in a direction which is orthogonal to the inspection objectconveyance direction, are wound around the two pulleys 29 and 29 whichare located on the opposite side of the winding shaft 27 respectively,are guided to the lower side first suction conveyance unit 1 along thetwo grooves 26 and 26 which are formed in the two support legs 25 and 25and are coupled to two places of the platen 8 on which the two supportlegs 25 and 25 abut at respective leading ends thereof. In addition, thetwo suspension wires 30 and 30 of the inner two pulleys 28 b and 28 b inthe every two pulleys on the both ends of the winding shaft 27 areguided downward along the two grooves 26 and 26 which are formed in thetwo support legs 25 and 25 which are located directly under the wires 30and 30 and are coupled to two places of the platen 8 on which the twosupport legs 25 and 25 abut at respective leading ends thereof.

A handle 31 which is rotationally movable through 360 degrees isinstalled on the wall of the first support section 21 which is oppositeto the wall on which the winding shaft 27 is installed with the conveyorbelt 6 being sandwiched. Although details are not illustrated, a rotaryshaft of the handle 31 is coupled to the winding shaft 27 in linkagewith the winding shaft 27 via a transmission mechanism such as a belt, apulley, a worm, a wheel and so forth. Accordingly, it becomes possibleto wind the suspension wires 30 on the pulleys 28 a and 28 b, to liftthe platen 8, to press the platen 8 against the leading ends of the foursupport legs 25 of the first support section 21 with necessary force andthereby to position the platen 8 by rotationally moving the windingshaft 27 in a predetermined direction by operating the handle 31. Here,since each suspension wire 30 is arranged in the groove 26 of eachsupport leg 25 and is coupled to the platen 8, force that the suspensionwire lifts the platen 8 directly works on a position on which eachsupport leg 25 abuts. Accordingly, an action of fixing the platen 8(that is, the first suction conveyance unit 1) onto the support legs 25becomes sure. Incidentally, although force which is necessary to liftthe first suction conveyance unit 1 with the suspension wire 30 dependson weight and so forth of each component, the force may be set to, forexample, 7N for every suspension wire 30, that is, to 28N in total forthe four suspension wires 30.

The first support section 21 on which the first inspection section 11 isloaded positions the platen 8 so as to match a virtual plane which isdefined by the leading ends of the four support legs 25 and fixes theplaten 8 at a position concerned with the necessary force in this way.Accordingly, the first inspection section 11 which is attached to apredetermined position of the first support section 21 becomes parallelwith the inspection object conveyance surface which faces the firstinspection section 11 and a distance between the first inspectionsection 11 and the conveyance surface reaches a fixed value which isdetermined in advance. In addition, even when the platen 8 is not in itsoriginal flattened surface form and there are some problems in flatness,it is also possible to correct the flatness of the platen 8 with the aidof force which works to pull the platen 8 with the suspension wires 30and to bring the platen 8 into abutment on the support legs 25.

Although description is made on the assumption that the inspectionsections 11 and 12 of the present embodiment are configured by the CISs,in general, the CIS is shallow in depth of field and a high arrangementaccuracy is required for obtaining an expected reading accuracy. Forexample, tolerance when setting to a distance of about 12 mm is about±0.2 mm. Accordingly, the high accuracy becomes necessary forpositioning of the CISs and the inspection object conveyance surface.However, according to the present embodiment, the first inspectionsection 11 is attached to the first support section 21 so as to beparallel with the virtual plane which is configured by respectiveleading end faces of the four support legs 25 which are formed on thefirst support section 21 and the platen 8 is fixed in the virtual planeby abutting the respective support legs 25 of the first support section21 on the platen 8. Thereby, the platen 8 becomes parallel with thefirst inspection section 11 and it becomes possible to properly inspectthe images on the inspection object which is conveyed by the firstsuction conveyance unit 1 with expected accuracy by the first inspectionsection 11.

Although the first support section 21 and the first suction conveyanceunit 1 are described above as the mechanism which performs positioningby pulling the first and second suction conveyance units 1 and 2 withthe suspension wires 30 into abutment on the support legs 25 of thefirst and second support sections 21 and 22 respectively, the secondsupport section 22 and the second suction conveyance unit 2 areconfigured as the mechanism which is almost the same as that of thefirst support section 21 and the first suction conveyance unit 1functionally, and therefore the description thereof is omitted byquoting the description of the first support section 21 and so forth.However, as illustrated on the right side in FIG. 5, the direction ofthe force and so forth of the second support section 22 is differentfrom that of the first support section 21 and so forth in that in thesecond support section 22, the second suction conveyance unit 2 which islocated above the second support section 22 is pulled downward with thefour suspension wires 30 into abutment on the upper end faces of theupward protruding four support legs 25 as illustrated on the right sidein FIG. 5. Incidentally, the first and second support sections 21 and 22of the present embodiment are configured to position the platen 8 so asto match the virtual plane which is defined by the leading ends of thefour support legs 25. However, it is sufficient that the virtual planebe uniquely determined by the leading ends of the support legs 25 andtherefore three or more support legs 25 may be formed. In addition, thepositioning accuracy of the platen 8 may be further increased by formingfive or more support legs 25.

As illustrated particularly in FIG. 4 to FIG. 7, in the first supportsection 21, the long support shaft 23 which is orthogonal to theinspection object conveyance direction is bridged on the upstream aidesof one pair of walls of the first support section 21 which is parallelwith the inspection object conveyance direction. Both ends of the longsupport shaft 23 project to the outside of the walls and the longsupport shaft 23 is coupled to the frame (not illustrated) of the imageinspection device 200 to be rotationally movable as indicated by abidirectional arrow around the long support shaft 23 in FIG. 5. That is,the first support section 21 is attached to be rotationally movable inan orientation that the downstream side or the upstream side of theconveyor belt 6 vertically swings around the long support shaft 23. Inaddition, in the first support section 21, a lower end of a couplingplate 32 which extends upward is fixed to downstream-side central partsof one pair of walls of the first support section 21 which is orthogonalto the inspection object conveyance direction. An upper end of thecoupling plate 32 is coupled to the frame (not illustrated) of the imageinspection device 200 to be rotationally movable by the short supportshaft 24 which is parallel with the inspection object conveyancedirection. A central axis of the short support shaft 24 is orthogonal toa central axis of the long support shaft 23 and is almost horizontal.The first support section 21 is supported on the frame in a state ofbeing rotationally movable in both diagonally forward direction anddiagonally rearward direction of the paper sheet around the shortsupport shaft 24 as indicated by a bidirectional arrow around the shortsupport shaft 24 in FIG. 5. Accordingly, the both ends of the longsupport shaft 23 serve as the support points A and B (see FIG. 3) whichsupport the first support section 21 on the frame to be rotationallymovable and the short support shaft 24 serves as the support point C(see FIG. 3) which supports the first support section 21 on the frame tobe rotationally movable. Since the second support section 22 has thestructure which is almost the same as the structure of the first supportsection 21 in function and is attached to the frame in the same way,description thereof is omitted by quoting the description of the firstsupport section 21 and so forth. A state where the first support section21 is supported at the support points A, B and C is not fixed in thisway. Therefore, in a case where certain external force is applied to theframe and thereby the frame is deformed, since the first support section21 is in a state of being supported to be rotationally movable in twoorthogonal planes which are illustrated in FIG. 5 respectively, theposture is maintained as soon as possible by releasing the force whichis transmitted from the frame so as to avoid deformation of the firstsupport section 21 and occurrence of a change which is harmful to itsarrangement relation with the second support section 22.

As described above, in the present embodiment, the first and secondsupport sections 21 and 22 which load the first and section inspectionsections 11 and 12 respectively are supported at the three points A, B,and C in a state of not being fixed, that is, being rotationally movablerelative to the frame of the image inspection device 200. Thus, thefollowing effects are obtained owing to the abovementioned structure.That is, in a case where the image inspection device 200 is installed ona floor which is low in flatness and in a case where although heights ofthe four support legs 25 of the image inspection device 200 are adjustedby an adjustor so as to cope with installation of the image inspectiondevice 200 on the floor which is low in flatness, height adjustment isnot performed perfectly and thereby a difference occurs among theheights of the support legs 25, the image inspection device 200 shiftsto an inclined posture which deviates from a necessary horizontal statein either case. Therefore, the external force is applied to the frame ofthe image inspection device 200 and distortion occurs. When thedistortion occurs in the frame, in a case where the first and secondsupport sections 21 and 22 are directly fixed to the frame, firstly, thedistortion also occurs in the first and second support sections 21 and22 and a positional relation between each of the first and secondinspection sections 11 and 12 which are attached to the first and secondsupport sections 21 and 22 respectively and the inspection objectconveyance surface changes. In addition, secondarily, also a mutualpositional relation between the first inspection section 11 and thesecond inspection section 12 changes. As a result, a trouble that thefirst and second inspection sections 11 and 12 erroneously detect theimages on the inspection object occurs.

However, according to the present embodiment, the first and secondsupport sections 21 and 22 which load the first and second inspectionsections 11 and 12 respectively are supported on the frame of the imageinspection device 200 at the three points A, B, and C in a non-fixedstate. Therefore, even in a case where useless external force is appliedto the frame of the image inspection device 200 and the distortionoccurs in the frame, the distortion is difficult to transmit to thefirst and second support section 21 and 22, the regular positionalrelation between each of the first and second inspection sections 11 and12 which are attached to the first and second support sections 21 and 22respectively and each of the first and second suction conveyance units 1and 2 is maintained, and a change is difficult to occur in the properlyset mutual positional relation between the first inspection section 11and second inspection section 12. Consequently, a trouble that the firstand second inspection sections 11 and 12 erroneously detect the imageson the inspection object does not occur.

As illustrated particularly in FIG. 6 and FIG. 8, the hanging preventionroller 16 is installed at a position which corresponds to a part underthe driven roller 4 of the second suction conveyance unit 2, that is,the position which is located under the upstream-side end of the secondsuction conveyance unit 2. As described before with reference to FIG. 2,the hanging prevention roller 16 is the hanging prevention member whichprevents the top edge of the inspection object which is introduced viathe intermediate guide plate 15 from hanging downward. The hangingprevention roller 16 has a roller portion which is divided into apectinate shape in an axial direction which is orthogonal to theinspection object conveyance direction. When the inspection object issent from the upstream first suction conveyance unit 1 into the secondsuction conveyance unit 2, the top edge of the inspection object abutson the hanging prevention roller 16 and runs on the hanging preventionroller 16 before the top edge of the inspection object hangs down underits own weight or because of downward curling, and then the inspectionobject is sandwiched between the conveyor belt 6 and the hangingprevention roller 16 and suction conveyance of the inspection object bythe second suction conveyance unit 2 is started. Alternatively, beforethe top edge of the inspection object hangs down, the top edge issandwiched between the hanging prevention roller 16 and the conveyorbelt 6 and the suction conveyance of the inspection object by the secondsuction conveyance unit 2 is started.

As described above, in the present embodiment, the hanging preventionroller 16 is installed at an inspection object delivering positionbetween the first suction conveyance unit 1 and the second suctionconveyance unit 2. Owing to the abovementioned structure, the followingeffects are obtained. That is, in the image inspection device 200according to the present embodiment, the first inspection section 11reads the image on the upper surface of the inspection object at theentrance of the first suction conveyance unit 1 and a timing that thesecond inspection section 12 starts reading the image on the lowersurface of the inspection object is set from a timing that the firstinspection section 11 performs image reading and a later conveyancelength. Propriety is decided by collating the images which are detectedby the CISs which configure the first and second inspection sections 11and 12 with original image data and a definition of the images which aredetected by the CISs is as high as about 300 dpi to about 600 dpi.Therefore, in a case where the top edge of the inspection object hangsdown when the inspection object is delivered between the first suctionconveyance unit 1 and the second suction conveyance unit 2, a time lagoccurs in a timing that the inspection object enters the second suctionconveyance unit 2 and erroneous image detection occurs when reading theimages on the inspection object by the second inspection section 12.However, according to the present embodiment, since the hangingprevention roller 16 is installed at the entrance of the second suctionconveyance unit 2, the trouble that the top edge of the inspectionobject hangs down under its own weight does not occur, no time lagoccurs in timing of image reading by the second inspection section 12which is set on the basis of the reading timing and so forth by thefirst inspection section 11, and the trouble of erroneous detection doesnot occur.

In addition, in a case when the top edge of the inspection object isseen along a line of sight which is parallel with the conveyancedirection, there are cases where wavy deformation (cockling) isobserved. Since occurrence of such deformation leads to a reduction inaccuracy of inspection by the inspection section such as the CIS and soforth and induces the erroneous detection, it is preferable to correctthe deformation to the greatest possible extent. In the presentembodiment, since the hanging prevention roller 16 sandwiches theinspection object between its pectinate roller portion and the conveyorbelt 6, cockling of the inspection object is corrected in shape in adirection that a crest of cockling is leveled and a depth of a trough isreduced and consequently the deformation is changed to a wavy form whichis smaller in cycle, the result which is the same as the result ofcockling correction is attained and an effect of preventing erroneousdetection of the images by the first and second inspection sections 11and 12 is obtained.

As illustrated particularly in FIG. 9 to FIG. 12, the first supportsection 21 is equipped with a first conveyance direction adjustmentelement which adjusts the direction that the inspection object isconveyed by the first suction conveyance unit 1. In the first supportsection 21, a fixing pin 35 is installed on one of walls making a pairwhich is parallel with the inspection object conveyance direction in astate of projecting downward. The fixing pin 35 is inserted into apositioning hole 36 which is formed in the platen 8. In addition, amovable pin 37 is installed on the other of the walls making the pairwhich is parallel with the inspection object conveyance direction in astate of projecting downward. The movable pin 37 is eccentricallyattached to a lower surface of a cylindrical operation member 38 whichis attached to the first support section 21 to be rotationally movableand is inserted into a slot 39 which is formed in the platen 8. Anoperation handle 40 which rotationally moves the operation member 38 isinstalled on a circumferential surface of the operation member 38. Ascale plate 41 which indicates an angle through which the operationmember 38 rotationally moves is attached around the operation member 38.

In a case where the first suction conveyance unit 1 is pulled up from astate which is illustrated in FIG. 10 with the suspension wires 30 (notillustrated in FIG. 10) and is brought into abutment on the four supportlegs 25 of the first support section 21, the fixing pin 35 is insertedinto the positioning hole 36, the movable pin 37 is inserted into theslot 39 and thereby the first suction conveyance unit 1 shifts to astate illustrated in FIG. 7. This state corresponds to the state whichis illustrated in FIG. 5 as a whole including the second suctionconveyance unit 2 and the second inspection section 12 and indicates astate in ordinary use. In a case of occurrence of a trouble ininspection accuracy of the first inspection section 11 and so forthcaused by insufficient flatness of the first inspection section 11 andthe first suction conveyance unit 1 under such ordinary use, it becomesnecessary to correct the direction that the inspection object isconveyed by the first suction conveyance unit 1.

In a case where the direction that the inspection object is conveyed bythe first suction conveyance unit 1 is corrected by using the firstconveyance direction adjustment element, first, the force of thesuspension wires 30 to pull up the first suction conveyance unit 1 isproperly reduced to shift to a state where the platen 8 is slidablerelative to the support legs 25. Then, as illustrated in FIG. 11 andFIG. 12, the operation member 38 is rotated by a necessary angle by theoperation handle 40 and the movable pin 37 is turned by a necessaryamount. It is possible to read a fluctuation of the angle according toan operation amount of the operation handle 40 from the scale plate 41.It is possible to adjust the orientation of the platen 8 of the firstsuction conveyance unit 1 by a maximum angle 9 around the fixing pin 35by performing such operations as described above. After adjustment, theforce of pulling-up by the suspension wires 30 is properly increasedthereby to fix the platen 8 to the support legs 25.

As described above, in the present embodiment, the mechanism whichadjusts the orientations of the first and second suction conveyanceunits 1 and 2 relative to the first and second support sections 21 and22 which load the first and second inspection sections 11 and 12respectively and thereby changes the inspection object conveyancedirection is installed. Therefore, in a case where a trouble occurs inthe positional relation between each of the first and second inspectionsections 11 and 12 and the inspection object conveyance direction forsome reasons, it is possible to correct the positional relation betweeneach of the inspection sections 11 and 12 and the inspection objectconveyance direction by operating the operation handle 40 and thereby toprevent occurrence of the erroneous detection. In addition, in a casewhere skewing of the inspection object occurs on the first suctionconveyance unit 1, a timing that the top edge of the inspection objectreaches the hanging prevention roller 16 is delayed when delivering theinspection object to the second suction conveyance unit 2 and therebythere is the possibility that the effect of preventing hanging by theaforementioned hanging prevention roller 16 may be reduced. However, itbecomes possible to surely secure the effect of hanging prevention bythe aforementioned hanging prevention roller 16 by adjusting theinspection object conveyance direction of the upstream side firstsuction conveyance unit 1 by operating the operation handle 40 so as tocorrect skewing of the inspection object and making the respectiveconveyance directions of the first suction conveyance unit 1 and thesecond suction conveyance unit 2 match each other.

Incidentally, a second conveyance direction adjustment element whichadjusts the direction that the inspection object is conveyed by thesecond suction conveyance unit 2 is installed also on the second supportsection 22 similarly to the first support section 21. However, theconfiguration of the second conveyance direction adjustment element isthe same as the structure of the first conveyance direction adjustmentelement in function and therefore repetitive description is avoided byquoting the description of the first conveyance direction adjustmentelement.

Modified Examples of Image Inspection Device According to Embodiment

Modified examples of the image inspection device 200 according to theembodiment of the present invention will be described with reference toFIG. 13 to FIG. 18.

FIG. 13 is a schematic front view illustrating a first modified exampleof the image inspection device 200. Although an image inspection device200 a according to a first modified example is the same as the imageinspection device 200 according to the embodiment in that the firstsuction conveyance unit 1 and the second suction conveyance unit 2 arearranged on the upstream side and the downstream side respectively alongthe inspection object conveyance direction, the conveyance surface ofthe second suction conveyance unit 2 has an angle which is inclineddownward toward the downstream side relative to the conveyance surfaceof the first suction conveyance unit 1.

Although, in the embodiment, the respective conveyance directions of thefirst suction conveyance unit 1 and the second suction conveyance unit 2match each other, in such a configuration, there are cases where the topedge of the inspection object which is delivered to the second suctionconveyance unit 2 hangs down and therefore the inspection object is notsucked onto the second suction conveyance unit 2 properly and deliveryof the inspection object is not smoothly performed. In such a case, thedownstream-side end of the second suction conveyance unit 2 is loweredslightly downward so as to make the above-described inclined angle as inthe first modified example. For setting the inclined angle, it ispossible to adjust the inclined angle by reducing tension of thesuspension wire 30 which suspends the second suction conveyance unit 2on the downstream side in comparison with the tension on the upstreamside.

A specific example of the inclined angle will be described. For example,paper and so forth of a thickness which is at least about 200 g/cm² inweighting is strong in tensility and therefore this paper is difficultto hang down when delivered. Therefore, it is preferable to set an anglebetween the conveyance surface of the first suction conveyance unit 1and the conveyance surface of the second suction conveyance unit 2 toabout 177 degrees which is not more than 180 degrees in the angle whichis measured under both the first and second suction conveyance units 1and 2. That is, in this case, an angle by which the downstream-side endof the second suction conveyance unit 2 is lowered is about threedegrees. For example, in a case of thin paper which is about 40 g/cm² inweighting, since the thin paper is weak in tensility and is easy to hangdown when delivered. Therefore, it is preferable to set the anglebetween the conveyance surface of the first suction conveyance unit 1and the conveyance surface of the second suction conveyance unit 2 toabout 170 degrees in the angle which is measured under both the suctionconveyance units 1 and 2. That is, an angle by which the downstream-sideend of the second suction conveyance unit 2 is lowered is about 10degrees. According to knowledge which is based on two examples that theinventors of the present invention have learned in this way, although itis preferable to set the inclined angle of the conveyance surface of thesecond suction conveyance unit 2 which is measured under both thesuction conveyance units 1 and 2 in a range from about 180 degrees toabout 170 degrees, there may be cases where a favorable angle range isincreased from 170 degrees by further several degrees under conditionswhich are different from those of the above-described two examples.

According to the image inspection device 200 a, even in a case where thetop edge of the inspection object which is conveyed from the firstsuction conveyance unit 1 to the second suction conveyance unit 2 hangsdown from the conveyance surface of the first suction conveyance unit 1downward due to the paper quality and so forth, the inspection object ispressed against the conveyance surface of the second suction conveyanceunit 2 which is inclined downward toward the downstream side andtherefore the inspection object is surely sucked and held on theconveyance surface and is stably conveyed toward the downstream side.

In addition, in the image inspection device 200 a, the angle which isinclined downward toward the downstream side of the conveyance surfaceof the second suction conveyance unit 2 may be set in accordance withimage formation conditions when forming the images on the inspectionobject. Here, as the image formation conditions, an orientation of theinspection object, a printing amount, arrangement balance of a printingrange in an image forming surface on the inspection object and so forthmay be given by way of example in addition to the kind of the inspectionobject which is expressed by the above-described weighting. Theaforementioned inclined angle may also be set to a proper value manuallyor automatically in accordance with these image formation conditions.

FIG. 14 is a schematic front view illustrating a second modifiedexample.

In an image inspection device 200 b according to the second modifiedexample, the conveyance surface of the downstream-side end of the firstsuction conveyance unit 1 and the conveyance surface of theupstream-side end of the second suction conveyance unit 2 are mutuallysuperimposed. Other configurations are the same as the configurations ofthe image inspection device 200 according to the embodiment. On a partwhere the two conveyance surfaces are mutually superimposed, the twoconveyor belts 6 and 6 face each other leaving a space of not more thanabout 0.5 mm in a vertical direction. As one example, since there aremany cases where a thickness of paper on which images are formed by theimage forming apparatus is about 0.2 mm in a case of thick paper, insuch a case, when a space between the two conveyor belts 6 and 6 is notmore than about 0.5 mm, there is no trouble in delivery of theinspection object. According to the second modified example, there areeffects that it is not necessary to install a mechanism (for example,the intermediate guide plate 15 illustrated in FIG. 2) used for deliveryof the inspection object between the upstream-side first suctionconveyance unit 1 and the downstream-side second suction conveyance unit2 and delivery is performed smoothly.

FIG. 15 is a schematic front view illustrating a third modified example.

In an image inspection device 200 c according to the third modifiedexample, cameras 11 a and 12 a and CISs 11 b and 12 b are installed onthe first suction conveyance unit 1 and the second suction conveyanceunit 2 respectively as the inspection sections. In both of the first andsecond suction conveyance units 1 and 2, the CISs 11 b and 12 b whichare relatively high in required arrangement accuracy (shallow in depthof field) are arranged relatively on the downstream side of theinspection object conveyance direction, and the cameras 11 a and 12 awhich are relatively low in required arrangement accuracy (deep in depthof field) are arranged relatively on the upstream side of the inspectionobject conveyance direction. Other configurations are the same as theconfigurations of the image inspection device 200 according to theembodiment. In the first and second suction conveyance units 1 and 2,the force of sucking the inspection object which is being conveyed ishigher in a state where the inspection object is sucked onto a partwhich reaches the downstream side of the conveyor belt 6 and is conveyedwith most of the holes closed than in a state where the inspectionobject is sucked only onto an upstream side part of the conveyor belt 6and is conveyed with most of the holes not closed. That is, in a casewhere cockling and curling are observed on the paper, the paper isdifficult to closely adhere to the conveyor belt 6 in the former stateand the paper is easy to closely adhere to the conveyor belt 6 in thelatter case. Therefore, it becomes possible to arrange different kindsof inspection sections 11 and 12 with arrangement accuracies which arenecessary for making the inspection sections 11 and 12 function withrespective inspection accuracies and to secure the levels of theinspection accuracies of the respective inspection sections 11 and 12 byarranging the cameras 11 a and 12 a which are relatively low in accuracy(deep in depth of field) and the CISs 11 b and 12 b which are relativelyhigh in accuracy (shallow in depth of field) on the respective first andsecond suction conveyance units 1 and 2 as described above.

FIG. 16 is a schematic front view illustrating a fourth modifiedexample.

An image inspection device 200 d according to the fourth modifiedexample has a hanging prevention member 42 which is formed by extendinga plate body which is located under the intermediate guide plate 15 upto a part under the upstream-side end of the second suction conveyanceunit 2 between the first suction conveyance unit 1 and the secondsuction conveyance unit 2. Other configurations are the same as theconfigurations of the image inspection device 200 according to theembodiment. Owing to arrangement of the hanging prevention member 42,the effect of preventing the top edge of the inspection object which isdelivered from the first suction conveyance unit 1 to the second suctionconveyance unit 2 from hanging down under its own weight and due tooccurrence of curling and so forth is obtained as in the case of theaforementioned hanging prevention roller 16 (see FIG. 2, FIG. 6 and soforth).

FIG. 17 is a schematic front view illustrating a fifth modified example.

In an image inspection device 200 e according to the fifth modifiedexample, a skew correction roller 43 which corrects skewing of theinspection object which is sent from the upstream side of the firstsuction conveyance unit 1 is installed adjacent to the upstream side ofthe first suction conveyance unit 1. The skew correction roller 43 isput on standby in a stopped state and starts rotating in the inspectionobject conveyance direction when the inspection object (the printingpaper) abuts on the roller 43. A top edge sensor 44 (see FIG. 4 and FIG.5) which detects the top edge of the inspection object is installedright next to the upstream side of the skew correction roller 43. Whenthe top edge sensor 44 detects the top edge of the inspection object,the control unit which receives a detection signal from the top edgesensor 44 drives the skew correction roller 43. Other configurations arethe same as the configurations of the image inspection device 200according to the embodiment. Owing to installation of the skewcorrection roller 43, even in a case where skewing occurs on theprinting paper (the inspection object) which is sent from theupstream-side printing device 100, it becomes possible to correctskewing of the printing paper and to send the printing paper to thefirst inspection section 11 in a proper posture.

FIG. 18 is a schematic front view illustrating a sixth modified example.

In an image inspection device 200 f according to the sixth modifiedexample, the CISs 11 b and 12 b are installed on the first suctionconveyance unit 1 and the second suction conveyance unit 2 respectivelyas the inspection sections. The CISs 11 b and 12 b as the inspectionsections are arranged in the vicinity of the downstream-side ends ofboth the first suction conveyance unit 1 and the second suctionconveyance unit 2. Other configurations are the same as theconfigurations of the image inspection device 200 according to theembodiment. In the first and second suction conveyance units 1 and 2,the force of sucking the inspection object which is conveyed is higherin a state where the inspection object is sucked onto the part whichreaches the downstream side of the conveyor belt 6 and is conveyed withmost of the holes closed than in a state where the inspection object issucked only onto the upstream side part the conveyor belt 6 and isconveyed with most of the holes not closed. That is, in the first andsecond suction conveyance units 1 and 2, as conveyance is promotedtoward the downstream side, force that the inspection object which isconveyed is held by the conveyor belt 6 is increased further and holdingis stabilized further. Therefore, in view of a fact that the CISs 11 band 12 as the inspection sections are high in arrangement accuracy whichis necessary for making the CISs 11 b and 12 b function with expectedinspection accuracy, the CIDs 11 b and 12 b are arranged on thedownstream sides of the respective first and second suction conveyanceunits 1 and 2 as described above. Thereby, the inspection object whichis conveyed by the first and second suction conveyance units 1 and 2down to the downstream side is stably held on the conveyor belt 6 withthe aid of sufficient suction force, and it becomes possible to detectthe images on the inspection object by the CISs 11 b and 12 b withexpected high accuracy.

In a case where the top edge of the inspection object is located on theupstream side of the conveyor belt 6 and suction force of a negativepressure and so forth is low, since a rear edge of the inspection objecthas not yet entered the first suction conveyance unit 1, suction bondingis not performed and the first suction conveyance unit 1 is in a statewhich is unstable in conveyance of the inspection object. However, whenthe top edge of the inspection object reaches the rear end of the firstsuction conveyance unit 1, the entire inspection object is sucked andbonded onto the conveyance surface, conveyance of the inspection objectis stabilized, and the possibility that the inspection object mayflutter in a height direction is reduced. Then, when the rear edge ofthe inspection object reaches the first inspection section 11 b which islocated on the downstream side of the first suction conveyance unit 1,for example, the negative pressure which works on the rear edge of theinspection object becomes lower. However, the top edge of the inspectionobject is sucked onto the conveyance surface of the downstream-sidesecond suction conveyance unit 2, and even when the negative pressure islowered only on the rear edge of the inspection object, it becomespossible to maintain a stable conveyance state with the aid of inertiaof a state where stable conveyance is performed in a state where thenegative pressure is high until just before reaching here. However, itis possible to maintain the stable state only with the aid of theabove-described inertia.

Incidentally, when the inspection object enters the suction conveyanceunit concerned, the rear edge side of the inspection object which hasnot yet entered the suction conveyance unit concerned irregularly moveswith ease because movement in a direction other than the conveyancedirection is not restricted. On the other hand, since the top edge sideof the inspection object which has entered the suction conveyance unitconcerned is pressed against the conveyor belt 6 of the suctionconveyance unit concerned by the press roller 14 and is sucked andbonded onto the conveyor belt 6, the top edge side of the inspectionobject is difficult to move. When conveyance is further promoted, anarea of the inspection object which is sucked and bonded onto theconveyor belt 6 by suction is gradually increased and conveyancestability is increased further. Then, when the inspection object isdischarged from the suction conveyance unit concerned, most of the areaof the inspection object is sucked and bonded onto the conveyor belt 6and therefore the inspection object is conveyed in a sufficiently stablestate. A state where the inspection object is sucked and bonded onto theconveyor belt 6 is more and more stabilized as the inspection object isconveyed in this way. A state where the stability in conveyance isfurther maintained is described using the term “inertia” or described inthe expression using the term “inertia” as described above in thepresent specification.

FIG. 19 is a perspective front view illustrating a seventh modifiedexample.

An image inspection device 200 g according to the seventh modifiedexample includes the first suction conveyance unit 1 and the secondconveyance unit 2. Only the upstream-side first suction conveyance unit1 is illustrated in FIG. 19 along a line of sight seeing downwarddiagonally from above diagonally on the downstream side of the frontview, and illustration of the downstream-side second suction conveyanceunit 2 is omitted. In addition, in the configuration of the firstsuction conveyance unit 1, illustration of some structures is changed oromitted in FIG. 19 and description of the numerals to be assigned toconstituent elements is appropriately omitted. However, configurationsof constituent elements other than the inspection sections (for example,the first support section 21, respective parts which configure theconveyance direction adjustment element and so forth) are substantiallythe same as the configurations of the above-described embodiment and themodified example and therefore repetitive description of these parts isavoided by quoting the preceding description in principle. Incidentally,in FIG. 19, the inspection object conveyance surface is the frontsurface of the conveyor belt 6 onto which the inspection object issucked and bonded, and the inspection object conveyance direction isindicated by an arrow Y which is parallel with the conveyance surface.In addition, a width direction of the inspection object which isorthogonal to the inspection object conveyance direction Y is indicatedby an arrow X.

As illustrated in FIG. 19, in the first suction conveyance unit 1 of theimage inspection device 200 g, the CIS 11 b as the first inspectionsection is installed relatively on the upstream side (the left side inFIG. 19) of the inspection object conveyance direction Y. The CIS 11 bis an element which inspects the image on the front surface of theinspection object in the linear inspection region on the inspectionobject which is parallel with the width direction X, an inspection rangeof the CIS 11 b sufficiently covers a widthwise length of the image onthe inspection object to be inspected, and it is possible to obtain dataon all images which are formed on the inspection object from pixel datawhich is read out of each of many linear inspection regions which arearrayed in the conveyance direction Y. The depth of field, thearrangement accuracy and so forth of the CIS 11 b are as describedabove.

As illustrated in FIG. 19, in the first suction conveyance unit 1 of theimage inspection device 200 g, the camera 11 a as the third inspectionsection is installed on the downstream side (the right side in FIG. 19)of the CIS 11 b of the inspection object conveyance direction Y. Thecamera 11 a is an element which inspects the image on the front surfaceof the inspection object in the planar inspection region which isparallel with the inspection object conveyance surface and has arectangular inspection range which allows reading of an image of apredetermined area (for example, a rectangular range of about 50 mm×100mm) which has a visually effective dimension in both the conveyancedirection Y and the width direction X just like, for example, a QR code.The depth of field, the arrangement accuracy and so forth of the camera11 a are as described above.

As illustrated in FIG. 19, the camera 11 a is loaded on a sliding-typemoving mechanism and is made movable in the inspection object widthdirection X, that is, the direction which is parallel with the linearinspection region on the front surface of the inspection object. In thefollowing, the moving mechanism will be described. A guide rail 50 isfixed to a frame of the image inspection device 200 g in parallel withthe width direction X above the first suction conveyance unit 1. Amoving body 51 is installed on the guide rail 50 to be movable along thewidth direction X. The moving body 51 is manually set to an optionalposition. However, the moving body 51 may be moved by a driving source(not illustrated). In this case, the moving body 51 may be set to theoptional position automatically by the driving source in accordance witha position of the image along the width direction X in the planarinspection region to be detected on the basis of detection informationfrom the upstream-side CIS 11 b or various control information and soforth from the control unit. Further, a semi-automatic system that thedriving source operates only when an operator closes a conduction switchand thereby the moving body 51 moves may also be adopted. An upper endof a stationary plate 52 is attached to a side face of the moving body51, and the stationary plate 52 is hanged more downward than the guiderail 50. The aforementioned camera 11 a is attached to an almost centralpart of a front surface of the stationary plate 52. The camera 11 aincludes a lens part 53 the focus of which is adjusted by turning afocus ring and a rotation mechanism part 54 which rotates the lens part53 in a rotation direction which is indicted by an arrow Z. An anglethat the lens part 53 is allowed to rotate by the rotation mechanismpart 54 is about 90 degrees. Both the focus ring of the lens part 53 andthe rotation mechanism part 54 are manually operated and when operatingthe focus ring and the rotation mechanism part 54, the operator works byopening an open/close door which is located on the front surface of theframe of the image inspection device 200 g and inserting his/her handinto a place concerned. One end of a bendable cable carrier 55 iscoupled to the stationary plate 52 to which the camera 11 a is attached.The cable carrier 55 bends and changes its direction by about 180degrees, and the other-end side of the cable carrier 55 is arrangedalong the guide rail 50 toward one end of the guide rail 50. A controlline 56 of the camera 11 a is drawn around along the cable carrier 55and is connected to the control unit (not illustrated).

Although not illustrated, the second suction conveyance unit 2 isarranged adjacent to the first suction conveyance unit 1 so as to beturned upside down relative to the first suction conveyance unit 1. Alsoin the second suction conveyance unit 2, the CIS 12 b as the secondinspection section is arranged relatively on the upstream side and thecamera 12 a as the fourth inspection section is arranged relatively onthe downstream side in arrangement which is similar to the arrangementof the CIS 11 b and the camera 11 a of the first suction conveyance unit1. Incidentally, in the second suction conveyance unit 2, the CIS 12 band the camera 12 a which is loaded on the moving mechanism are arrangedunder the second suction conveyance unit 2 facing upward contrary to theCIS 11 a and the camera 12 a of the first suction conveyance unit 1 andinspect the images on the back surface of the inspection object.

According to the image inspection device 200 g of the seventh modifiedexample, it becomes possible to perform linear inspection region-basedinspection on the images which are printed on the inspection object bythe upstream-side CIS 11 b and to perform inspection of the images (forexample, a bar code image and so forth) in a two-dimensional planarinspection region which is formed on a specific position of theinspection object by the downstream side camera 11 a. In this case, itis preferable to properly set a position of the camera 11 a along thewidth direction X in advance by such manual, automatic or semi-automaticoperation as described above in accordance with the position of theplanar inspection area which is formed on the inspection object alongthe width direction X. In addition, it is also preferable to set therectangular inspection range of the camera 11 a to an appropriatearrangement in a vertically long arrangement and a horizontally longarrangement in advance in accordance with the shape of the image in theplanar inspection region on the inspection object by operating therotation mechanism part 54 of the camera 11 a. Incidentally, a height ofthe camera 11 a which is measured from the conveyance surface is fixed,and the sheet-shaped inspection object (the sheet paper) is sucked andfixed onto the conveyance surface of the conveyor belt 6 across theentire surface and is in the stable state. Therefore, although thepossibility that the once focused camera 11 a may become out of focus islow, focusing of the camera 11 a may be confirmed as needed.

In addition, according to the image inspection device 200 g, theinspection object that the suction conveyance unit concerned conveys asa conveyance object is the sheet-shaped paper. Accordingly, unlike acase of conveying a bag and so forth having a structure that two sheetsof paper are superimposed in order to form a space in the bag, in theimage inspection device 200 g, the sheet-shaped inspection object issucked onto the conveyance surface of the conveyor belt 6 across theentire surface and is conveyed in a state where the vertical position isfixed. Accordingly, it becomes possible to sufficiently exhibit the highreading accuracy of the CIS 11 b which is shallower in depth of fieldthan the camera 11 a and for which the high arrangement accuracy isrequired in order to obtain the expected reading accuracy.

In addition, inspection of the inspection object on the first suctionconveyance unit 1 of the image inspection device 200 g is performed inthe following order: first, linear inspection region-based inspection isperformed by the CIS 11 b on the upstream side; and then inspection ofthe planar inspection region is performed by the downstream-side camera11 a. Therefore, in a case where behavioral abnormality of theinspection object and image abnormality are detected in line-by-lineimage inspection on the upstream side, a step of inspecting the planarinspection region on the downstream side is suspended by using thisabnormality detection as a trigger and thereby it becomes possible toomit useless inspection of the inspection object. A sorting device or adistribution device may be installed on the downstream side of the imageinspection device 200 g for an inspection object in which abnormality isdetected so as to sort or distribute the inspection object in which theabnormality is detected, then to guide the sorted or distributedinspection object to a path which is different from a path for aninspection object having no trouble and then to collect the sorted ordistributed inspection object. Incidentally, in a case where theabnormality is detected in inspection by the CIS 11 b, inspection by thecamera 11 a may be continued as it is and in regard to the inspectionobject in which the abnormality is detected, detection of abnormalitymay be left on inspection record, and image inspection may be performedagain by inputting the inspection object in which the abnormality isdetected on an inspection line later.

Further, according to the image inspection device 200 g, even when a jamoccurs on the inspection object delivery section which is locatedbetween the first suction conveyance unit 1 and the second suctionconveyance unit 2, at least the inspection section which is located onthe downstream side of the first suction conveyance unit 1 is the camera11 a which is movable in the width direction X and therefore in a casewhere the jam occurs in the vicinity of the camera 11 a, it is possibleto secure a workspace by moving the camera 11 a in the width direction Xand thereby to manually perform jam clearing work more easily.Incidentally, in a case where the configuration of the first suctionconveyance unit 1 is as described above and in the second suctionconveyance unit 2, the upstream side inspection section is configured bythe camera 12 a which is movable in the width direction X and thedownstream side inspection section is configured by the CIS 12 b, thenthe jam clearing work to be performed when the jam occurs on thedelivery section as described above becomes even more easily.

Further, in the image inspection device 200 g, when positionaldisplacement of the inspection object occurs in the width direction Xwhile the inspection object is conveyed, occurrence of a trouble thatthe planer inspection region does not enter the inspection range of thecamera 11 a which is set in alignment with the position of the planarinspection region (for example, the QR code) to make it impossible toperform inspection is conceivable. However, according to the imageinspection device 200 g, the CIS 11 b of the first suction conveyanceunit 1 is able to detect positions of edges of the inspection object inthe width direction X at both ends of the linear inspection region.Accordingly, in a case where the CIS 11 b performs inspection of thelinear inspection region a plurality of times and obtains a plurality ofpieces of data on the positions of the edges which are located on thesame sides in the width direction X, the control unit into which theplurality of pieces of data are input is able to decide whether theinspection object is displaced in the width direction X at once bycomparing the plurality of pieces of data with one another and is ableto calculate an amount of displacement immediately in a case where theinspection object is displaced in the width direction X. Then, thecontrol unit controls the moving mechanism for the camera 11 a which islocated on the downstream side in accordance with the displacementamount and thereby it becomes possible to correct the position of thecamera 11 a, in the width direction X, to make a new position of theplanar inspection region and the inspection range of the camera 11 amatch each other and thereby to make the camera 11 a properly performinspection of the planar inspection region.

FIG. 20 is a schematic front view illustrating an eighth modifiedexample.

In an image inspection device 200 h according to the eighth modifiedexample, the configuration of the conveyance mechanism centering aroundthe first suction conveyance unit 1 and the second suction conveyanceunit 2 is the same as the configuration of the conveyance mechanism ofthe image inspection device 200 according to the embodiment. Thus, thenumerals which are the same as those in FIG. 2 are assigned to thecorresponding constitutional elements and description thereof is omittedby quoting the description of the embodiment. In addition, the kind andthe number of the inspection sections and a way of arraying theinspection sections along the inspection object conveyance directionaccording to the kind is the same as those of the third modified exampleof the embodiment which is illustrated in FIG. 15.

That is, as illustrated in FIG. 20, in the image inspection device 200h, the camera 11 a as the first inspection section and the CIS 11 b asthe third inspection section are arrayed in this order when seen fromthe upstream side on the first suction conveyance unit 1, and the camera12 a as the second inspection section and the CIS 12 b as the fourthinspection section are arrayed in this order when seen from the upstreamside on the second suction conveyance unit 2. The configurations of theCISs 11 b and 12 b and the cameras 11 a and 12 a are as described beforedescription of this modified example. However, as a more specificarrangement example of the inspection sections, the height of the CISs11 b and 12 b which is measured from the conveyance surface of theconveyor belt 6 is set to about 24 mm, the height of the cameras 11 aand 12 a which is measured from the conveyance surface of the conveyorbelt 6 is set to about 120 mm in view of the fact that the cameras 11 aand 12 a are area cameras each having a wide-angle inspection range. Inaddition, the cameras 11 a and 12 a are loaded on the sliding-typemoving mechanism similarly to the cameras in the seventh modifiedexample which is illustrated in FIG. 19. As the description of themoving mechanism, the description of the moving mechanism of the seventhmodified example will be quoted.

In the first and second suction conveyance units 1 and 2, the force ofsucking the inspection object which is conveyed is higher in a statewhere the inspection object is sucked onto the part extending to thedownstream side of the conveyor belt 6 and is conveyed with most of theholes closed than in a state where the inspection object is sucked onlyonto the upstream-side part of the conveyor belt 6 and is conveyed withmost of the hole not closed. That is, the force of sucking theinspection object is relatively weak on the upstream side of theconveyer belt 6 and displacement of a height-direction position of theinspection object is easy to occur. In contrast, the suction force isrelatively strong on the downstream side of the conveyor belt 6 anddisplacement of the height-direction position of the inspection objectis difficult to occur. Accordingly, in the image inspection device 200h, the CISs 11 b and 12 b which are relatively high in requiredarrangement accuracy (shallow in depth of field) are arranged relativelyon the downstream side of the inspection object conveyance direction,and the cameras 11 a and 12 a which are relatively low in requiredarrangement accuracy (deep in depth of field) are arranged relatively onthe upstream side of the inspection object conveyance direction.Therefore, it becomes possible to arrange the different kinds of theinspection sections with arrangement accuracies which are necessary tomake the inspection sections function with their expected inspectionaccuracies and it becomes possible to surely secure the levels of theexpected inspection accuracies of the respective inspection sections.

As described above, in the seventh modified example which is describedwith reference to FIG. 19 and the eighth modified example which isdescribed with reference to FIG. 20, the cameras 11 a and 12 a arearranged on the upstream sides of the respective suction conveyanceunits 1 and 2 respectively, the CISs 11 b and 12 b are arranged on thedownstream sides of the respective suction conveyance units 1 and 12respectively, and the cameras 11 a and 12 a are made to be movable in adirection which is parallel with the linear inspection region. However,in a case where the images which are formed on the inspection object asobjects for inspection are fixedly present only on specific positions ina direction which is parallel with the linear inspection region andconveyance operations of the suction conveyance units 1 and 2 arestable, and therefore the position of the inspection object in thedirection which is parallel with the linear inspection region is stable,positions of the cameras 11 a and 12 a may be fixed in alignment withthe positions of the image in the direction which is parallel with thelinear inspection region without making the cameras 11 a and 12 amovable.

A ninth modified example will be described with reference to FIG. 1.

In the modified examples which have been described so far, in a casewhere only the CIS is arranged on the suction conveyance unit concernedand in a case where both the IIS and the camera are arranged on thesuction conveyance unit concerned, in the both cases, there are caseswhere both the CIS and the camera are arranged relatively on theupstream side of the suction conveyance unit concerned and there arealso cases where both the CIS and the camera are arranged relatively onthe downstream side of the suction conveyance unit concerned. In amodified example which will be described in the following, on which sidethe CIS and the camera are to be arranged is determined between theupstream side and the downstream side of the conveyance direction on thebasis of a viewpoint of nipping force as to which inspection objectnipping force (or conveying force) is larger between the nipping forceof the device on the upstream side and the nipping force of the deviceon the downstream side between two mutually adjacent devices in theprinting device 100, the image inspection device 200, and thepost-processing device 300 which are illustrated in FIG. 1 as well as aview point of the inspection object conveyance path as to whichinspection object conveyance path 102 of which device is morecomplicated between the conveyance path of the device on the upstreamside and the conveyance path of the device on the downstream side alsobetween the two mutually adjacent devices in the printing device 100,the image inspection device 200, and the post-processing device 300.

In FIG. 1, in a case where the nipping force of the printing device 100is larger than the nipping force of the image inspection device 2 whichis located on the downstream side of the printing device 100, there arecases where conveyance of the inspection object becomes unstable on theupstream side of the image inspection device 200 which is adjacent tothe printing device 100, and the height-direction position of theinspection object fluctuates irregularly, and therefore it is preferableto arrange the camera (11 a or 12 a) which is the inspection section forwhich no high arrangement accuracy is required on the uppermost streamside of the image inspection device 200.

In FIG. 1, in a case where the nipping force of the image inspectiondevice 200 exceeds the nipping force of the printing device 100,conveyance of the inspection object is stable on the upstream side ofthe image inspection device 200 and the height-direction position of theinspection object is difficult to fluctuate, and therefore it ispreferable to arrange the CIS (11 b or 12 b) which is the inspectionsection for which the high arrangement accuracy is required on theuppermost stream side of the image inspection device 200.

In FIG. 1, in a case where the conveyance path 102 of the printingdevice 100 which is connected to the upstream side of the imageinspection device 200 is not linear and is bent just like a conveyancepath 102 a which is indicated by a dashed line, the possibility that apaper jam may occur on the uppermost-stream side of the conveyance pathin the image inspection device 200 is increased. Accordingly, the camera(11 a or 12 a) is used as the inspection section to be arranged on theuppermost-stream side of the image inspection device 200 and the cameraconcerned is made movable in the width direction X by the aforementionedsliding type moving mechanism. Thereby, in a case where the paper jamoccurs on the uppermost-stream side of the conveyance path in the imageinspection device 200, it becomes possible to secure a workspace for jamclearance by moving the camera concerned and thereby the work for jamclearance is facilitated.

In FIG. 1, in a case where the conveyance path 102 of thepost-processing device 300 which is connected to the downstream side ofthe image inspection device 200 is not linear and is bent just like theconveyance path 102 a which is indicated by the dashed line, thepossibility that a paper jam may occur on the lowermost-stream side ofthe conveyance path of the image inspection device 200 is increased.Accordingly, the camera (11 a or 12 a) is used as the inspection sectionto be arranged on the lowermost-stream side of the image inspectiondevice 200, and the camera concerned is made movable in the widthdirection X by the aforementioned sliding type moving mechanism.Thereby, in a case where the paper jam occurs on the lowermost-streamside of the conveyance path in the image inspection device 200, itbecomes possible to secure a workspace for jam clearance by moving thecamera concerned and thereby the work for jam clearance is facilitated.

Incidentally, in the present embodiment and the modified examplesthereof, the first suction conveyance unit 1 is arranged in such amanner that the conveyance surface is located on the upper surface sideand the second suction conveyance unit 2 is arranged in such a mannerthat the conveyance surface is located on the lower surface side and isarranged adjacent to the conveyance surface of the first suctionconveyance unit 1 along the inspection object conveyance direction.However, there is no particular limitation on the paper conveyancedirection relative to the first and second suction conveyance units 1and 2. That is, for example, although in FIG. 2, the inspection objectis illustrated to be conveyed from left to right, the inspection objectmay be conveyed from right to left. In addition, in FIG. 2, arrangementof the first suction conveyance unit 1 and the second suction conveyanceunit 2 may be changed in such a manner that the first suction conveyanceunit 1 is located on the right side and the second suction conveyanceunit 2 is located on the left side. Also, in this case, the paper may beconveyed either rightward or leftward.

Incidentally, although belt suction conveyance using a fan is describedas the inspection object conveyance element in the present embodimentand the modified examples thereof, electrostatic suction conveyance,bonding conveyance by bonding using roller conveyance, and other typesof bonding conveyance using certain bonding elements may be used. Asbonding conveyance using the roller conveyance which is one example ofthe bonding conveyance, for example, it is possible to convey paper bymaking the paper bond to a roller by a roller conveyance element inwhich a bonding agent having a bond strength of such an extent that theinspection object does not fall under its own weight is applied onto aroller surface, and it is also possible to use this roller conveyancemember in place of the suction conveyance unit of the presentembodiment. Further, as bonding conveyance using other bonding elements,it is also possible to use bonding conveyance using belt conveyance inwhich the inspection object is conveyed by applying the above-describedbonding agent onto the conveyor belt. Incidentally, in a case ofperforming these types of bonding conveyance, a pee-ling section whichpeels the paper from the bonding agent on the conveyor belt or theroller may be installed. Inspection object conveyance is not limited tothe belt suction conveyance using the fan just like the conveyance ofthe present embodiment in this way. In addition, even in a case ofperforming the electrostatic suction conveyance and the bondingconveyance by the first and second suction conveyance units 1 and 2, theinspection section(s) may be arranged on the downstream sides of thefirst and second suction conveyance units 1 and 2. This is because, forexample, also in a case of performing the electrostatic suctionconveyance, an electrostatic suction area becomes larger on thedownstream aide than on the upstream side and suction is stabilized. Inaddition, also in a case of performing bonding conveyance by using theplurality of rollers in the first and second suction conveyance units 1and 2, suction is stabilized and conveyance is secured more in a statewhere the inspection object is conveyed by being bonded using two ormore roller on the downstream side than in a state where the inspectionobject is conveyed by being bonded using one roller on the upstreamside.

Further, as the one first inspection section (or the one secondinspection section) which is installed on the first conveyance unit (orthe second conveyance unit), CIS (contact image sensor), a camera, abarcode-reader and so forth may be specifically given by way of example;however, the first inspection section (or the second inspection section)may be an inspection device having function of reading images on otherprinciples. Further, the first inspection section (or the secondinspection section) may include other device having function exceptinspection as well as the inspection device.

Incidentally, although there are cases where the drawings which areappended to the present specification are schematically expressed in astate where scales, an aspect dimension ratio, shapes and so forth areappropriately changed from real ones for the convenience in view ofillustration and comprehensiveness, these are merely examples and do notlimit interpretation of the present invention. Accordingly, the presentinvention is not limited by the embodiment and the modified examplesthereof which are described using the appended drawings, and all theother feasible aspects, embodiments, operation technologies and so forthwhich would be conceived of by a person skilled in the art on the basisof the present embodiment and the modified examples thereof are includedin the scope of the present invention.

Sheet Feeders of Respective Aspects in Present Embodiment and ModifiedExamples Thereof and Effects Thereof

The image inspection devices 200, 200 a to 200 f according to a firstaspect each include:

the first suction conveyance unit 1 which is arranged in such a mannerthat the conveyance surface on which the sheet-shaped inspection objectis sucked and conveyed is located on the upper surface side;

the second suction conveyance unit 2 which is arranged adjacent to theconveyance surface of the first suction conveyance unit 1 along theinspection object conveyance direction in such a manner that theconveyance surface on which the sheet-shaped inspection object is suckedand conveyed is located on the lower surface side;

the first inspection section 11 which inspects the images on the frontsurface of the inspection object which is conveyed by the first suctionconveyance unit 1; and

the second inspection section 12 which inspects the images on the backsurface of the inspection object which is conveyed by the second suctionconveyance unit 2.

According to the image inspection devices 200, 200 a to 200 f accordingto the first aspect, the inspection object is stably conveyed in a stateof being sucked and held on the upper surface side of the first suctionconveyance unit 1, is stably conveyed in a state of being sucked andheld on the lower surface side of the second suction conveyance unit 2,and is stably delivered between the first suction conveyance unit 1 andthe second suction conveyance unit 2. Therefore, since the position andthe posture of the inspection object are stabilized while the inspectionobject is conveyed, the expected accuracy is maintained in inspection bythe first inspection section 11 and the second inspection section 12.

In the image inspection device 200 a according to a second aspect,

the first suction conveyance unit 1 and the second suction conveyanceunit 2 are arranged on the upstream side and the downstream siderespectively along the inspection object conveyance direction, and

the conveyance surface of the second suction conveyance unit 2 has theangle which is inclined downward toward the downstream side relative tothe conveyance surface of the first suction conveyance unit 1 and whichis necessary for stable conveyance of the inspection object, in theimage inspection devices according to the first aspect.

According to the image inspection device 200 a according to the secondaspect, since the conveyance surface of the second suction conveyanceunit 2 which is located on the downstream side of the inspection objectconveyance direction is inclined downward toward the downstream siderelative to the conveyance surface of the first suction conveyance unit1 which is located on the upstream side by the angle which is necessaryfor stable conveyance of the inspection object, the top edge of theinspection object which is conveyed from the first suction conveyanceunit 1 to the second suction conveyance unit 2 is pressed against theconveyance surface of the second suction conveyance unit 2 and thereforeis surely sucked and held on the conveyance surface and is stablyconveyed to the downstream side by the second suction conveyance unit 2even when the top edge hangs downward from the conveyance surface of thefirst suction conveyance unit 1 because of paper quality and so forth.

In the image inspection device 200 a according to a third aspect, theangle which is inclined downward toward the downstream side of theconveyance surface of the second suction conveyance unit 2 is set inaccordance with image forming conditions when forming the images on theinspection object, in the image inspection device 200 a according to thesecond aspect.

According to the image inspection device 200 a according to the thirdaspect, the angle which is inclined downward toward the downstream sideof the conveyance surface of the second suction conveyance unit 2 isappropriately set in accordance with the image forming conditions whenforming the images on the inspection object such as, for example, thekind of the inspection object, the orientation of the inspection object,the printing amount, and the arrangement balance of the printing rangein the image forming surface of the inspection object. Accordingly, theeffect that the top edge of the inspection object which is conveyed fromthe first suction conveyance unit 1 to the second suction conveyanceunit 2 is pressed against the conveyance surface of the second suctionconveyance unit 2 and thereby is surely sucked and held on theconveyance surface and is stably conveyed to the downstream side by thesecond suction conveyance unit 2 becomes more certain.

The image inspection devices 200, 200 a to 200 f according to a fourthaspect each have:

the first support section 21 to which the first inspection section 11 isattached and which is supported on the frame of the image inspectiondevice at the three places to be movable and is positioned relative tothe first suction conveyance unit 1; and

the second support section 22 to which the second inspection section 12is attached and which is supported on the frame of the image inspectiondevice at the three places to be movable and is positioned relative tothe second suction conveyance unit 2, in the image inspection devicesaccording to the first aspect.

According to the image inspection devices 200, 200 a to 200 f accordingto the fourth aspect, the first support section 21 and the send supportsection 22 are supported on the frame of the image inspection deviceconcerned at the three places to be rotatable respectively. Therefore,even in a case where the external force is applied to the frame and theframe is distorted due to inclined arrangement of the image inspectiondevice and so forth, since no harmful force is transmitted from theframe to the first support section 21 and the second support section 22,the first support section 21 and the second support section 22 are notdistorted. Accordingly, the positional relations between the firstinspection section 11 which is installed on the first support section 21and the first suction conveyance unit 1 and between the secondinspection section 12 which is installed on the second support section22 and the second suction conveyance unit 2 do not change from thenormal states respectively, and the positional relation between thefirst suction conveyance unit 1 and the second suction conveyance unit 2does not change. Accordingly, since the respective conveyance surfacesof the first suction conveyance unit 1 and the second suction conveyanceunit 2 maintain a mutually matched state and the inspection object isproperly inspected by the two inspection sections while beingcontinuously conveyed, the inspection accuracy is not lowered.

In the image inspection device 200 b according to a fifth aspect, partof the conveyance surface of the first suction conveyance unit 1 andpart of the conveyance surface of the second suction conveyance unit 2are mutually superimposed, in the image inspection devices according tothe first aspect.

According to the image inspection device 200 b according to the fifthaspect, since part of the conveyance surface of the first suctionconveyance unit 1 and part of the conveyance surface of the secondsuction conveyance unit 2 are mutually superimposed, the inspectionobject is directly delivered between the first suction conveyance unit 1and the second conveyance unit 2 and conveyance of the inspection objectis smoothly performed. In addition, it is not necessary to install theelement for delivering the inspection object between the first andsecond suction conveyance units 1 and 2, and the configuration issimplified in comparison with a case where this member is installed.

The image inspection device 200 c according to a sixth aspect furtherincludes:

the third inspection section 11 b which is arranged at the positionwhich is different from the position of the first inspection section 11a in the inspection object conveyance direction and inspects the imageson the front surface of the inspection object; and

the fourth inspection section 12 b which is arranged at the positionwhich is different from the position of the second inspection section 12a in the inspection object conveyance direction and inspects the imageson the back surface of the inspection object.

On the first suction conveyance unit 1, of the first inspection section11 a and the third inspection section 11 b, the inspection section 11 bfor which the relatively high arrangement accuracy is required isarranged relatively on the downstream side of the inspection conveyancedirection, and the inspection section 11 a is arranged relatively on theupstream side of the inspection object conveyance direction.

On the second suction conveyance unit 2, of the second inspectionsection 12 a and the fourth inspection section 12 b, the inspectionsection 12 b for which the relatively high arrangement accuracy isrequired is arranged relatively on the downstream side of the inspectionconveyance direction, and the inspection section 12 a is arrangedrelatively on the upstream side of the inspection object conveyancedirection.

According to the image inspection device 200 c according to the sixthaspect, although two inspection sections are installed respectively onthe first suction conveyance unit 1 and the second suction conveyanceunit 2, also on either suction conveyance unit, of the two inspectionsections, the inspection section for which the required arrangementaccuracy is relatively high is arranged relatively on the downstreamside of the inspection object conveyance direction, and the inspectionsection for which the required arrangement accuracy is relatively low isarranged relatively on the upstream side of the inspection objectconveyance direction. In the first and second suction conveyance units 1and 2, since the stability of the inspection object which is conveyed bysuction is higher in the state where the inspection object is conveyedwhile being sucked onto the part which reaches the downstream side ofthe suction conveyance unit concerned than in the case where theinspection object is conveyed while being sucked onto only the upstreamside part of the suction conveyance unit concerned, arrangement of therespective inspection sections on the respective suction conveyanceunits 1 and 2 is made as mentioned above and thereby it becomes possibleto arrange the respective inspection sections with the arrangementaccuracies which are necessary to make the respective inspectionsections function with the expected inspection accuracies and tomaintain inspection object inspection accuracies at expected levels ofthe respective inspection sections.

The image inspection device 200 g according to the seventh aspectfurther includes:

the third inspection section which is arranged at the position which isdifferent from the position of the first inspection section 11 a alongthe inspection object conveyance direction and inspects the images onthe front surface of the inspection object; and

the fourth inspection section 12 b which is arranged at the positionwhich is different from the position of the second inspection section 12a along the inspection object conveyance direction and inspects theimages on the back surface of the inspection object.

One of the first inspection section 11 a and the third inspectionsection 11 b is arranged relatively on the upstream side of theinspection object conveyance direction and inspects the images on thefront surface of the inspection object in the linear inspection regionwhich is vertical to the inspection object conveyance direction and isparallel with the conveyance surface, and the other of the firstinspection section 11 a and the third inspection section 11 b isarranged relatively on the downstream side of the inspection objectconveyance direction and inspects the images on the front surface of theinspection object in the planar inspection region which is parallel withthe conveyance surface, and

one of the second inspection section 12 a and the fourth inspectionsection 12 b is arranged relatively on the upstream side of theinspection object conveyance direction and inspects the images on theback surface of the inspection object in the linear inspection regionwhich is vertical to the inspection object conveyance direction and isparallel with the conveyance surface, and the other of the secondinspection section 12 a and the fourth inspection section 12 b isarranged relatively on the downstream side of the inspection objectconveyance direction and inspects the images on the back surface of theinspection object in the planar inspection region which is parallel withthe conveyance surface.

According to the image inspection device 200 g according to the seventhaspect, in the respective suction conveyance units 1 and 2, in a casewhere behavior abnormality and image abnormality of the inspectionobject are detected in inspection of the images in the linear inspectionregion by the upstream-side inspection section, the step of inspectingthe images in the planar inspection region by the downstream sideinspection section is suspended by using this abnormality detection asthe trigger and thereby it becomes possible to eliminate uselessinspection of the images on the inspection object concerned.

In the image inspection device 200 g according to an eight aspect,

the other of the first inspection section 11 a and the third inspectionsection 11 b is movable in the direction which is parallel with thelinear inspection region, and

the other of the second inspection section 12 a and the fourthinspection section 12 b is movable in the direction which is parallelwith the linear inspection region, in the image inspection deviceaccording to the seventh aspect.

According to the image inspection device 200 g according to the eighthaspect, even when the inspection object jam occurs between the firstsuction conveyance unit 1 and the second suction conveyance unit 2,since the inspection section which is located on the downstream side ofthe first suction conveyance unit 1 is the inspection section which ismovable in the direction which is the inspection object width directionand is parallel with the linear inspection region, in a case where thejam occurs in the vicinity of the inspection section concerned, it ispossible to perform manual jam clearance work more easily by moving theinspection section concerned in the direction which is parallel with thelinear inspection region.

In the image inspection devices 200, 200 a to 200 f accruing to a ninthaspect, on at least one of the first suction conveyance unit 1 and thesecond suction conveyance unit 2, at least one of the first inspectionsection 11 a and the second inspection section 12 a is installed on atleast one of the upstream-side end and the downstream-side end of theinspection object conveyance direction.

According to the image inspection devices 200, 200 a to 200 f accordingto the ninth aspect, since the first and second suction conveyance units1 and 2 are mechanisms which convey the sheet-shaped inspection objectin a state where the inspection object is sucked onto the conveyancesurfaces thereof, the conveyance surfaces are made open, and there existno constitutional elements of the first suction conveyance unit 1 andthe second suction conveyance unit 2 which would become obstacles. Then,in the open conveyance surfaces, parts on which the first inspectionsection 11 a and the second inspection section 12 a are arranged arelimited to only at least one of the upstream-side end and thedownstream-side end. Accordingly, the possibility that the sheet-shapedinspection object may be jammed on the conveyance surface(s) of thefirst suction conveyance unit 1 and/or the second suction conveyanceunit 2 is low. However, even when the inspection object jam occurs, mostparts of the conveyance surfaces are made open, the first inspectionsection 11 a and the second inspection section 12 a which are arrangedon the ends of the conveyance surfaces do not become the obstacles whenremoving the jammed inspection object from the conveyance surfaceconcerned, and it is possible to perform the jam clearance work withease.

In the image inspection devices 200 c and 200 f according to a tenthaspect, at least one of the first inspection section 11 a and the secondinspection section 12 a is installed on the downstream-side end of atleast one of the first suction conveyance unit 1 and the second suctionconveyance unit 2, in the image inspection devices according to thefirst aspect.

According to the image inspection devise 200 c and 200 f according tothe tenth aspect, on the first suction conveyance unit 1 and the secondsuction conveyance unit 2, the stability which is attained by suction ofthe inspection object which is conveyed is higher in the state where theinspection object is sucked onto the conveyance surface across the widerarea reaching the downstream side of the conveyance surface and theeffect of suction acts on most of the conveyance surface than in thestate where the inspection object is sucked only onto the upstream sideof the conveyance surface and the effect of suction does not act on mostof the conveyance surface. Accordingly, owing to installation of thefirst inspection section 11 b and the second inspection section 12 brespectively on the downstream-side ends of the first suction conveyanceunit 1 and the second suction conveyance unit 2 in the conveyancedirection, it becomes possible to inspect the images on the inspectionobject in a state where holding of the inspection object is certain andthe position and the posture of the inspection object are stabilized andto obtain the effect that the inspection accuracy is improved.

In the image inspection devices 200, 200 a to 200 e according to aneleventh aspect, at least one of the first inspection section 11 a andthe second inspection section 12 a is installed on the upstream-side endof at least one of the first suction conveyance unit 1 and the secondsuction conveyance unit 2, in the image inspection devices according tothe first aspect.

According to the image inspection devices 200, 200 a to 200 e accordingto the eleventh aspect, since the first inspection section 11 or 11 aand the second inspection section 12 or 12 a are arranged in thevicinity of the upstream-side ends of the first suction conveyance unit1 and the second suction conveyance unit 2 respectively, in a case wherethe results of image detection by the first inspection section 11 or 11a and the second inspection section 12 or 12 a are utilized on thedownstream side, it is preferable to arrange the inspection sections inthe vicinity of the upstream side ends of the suction conveyance unitsbecause sufficient time is secured for utilization of the imagedetection results. For example, in a case where post-processing isperformed on the inspection object on the basis of the inspectionresults in the post-processing device which is located on the rear stageof the image inspection devises 200, 200 a to 200 e, since the firstinspection section 11 or 11 a and the second inspection section 12 or 12a are located on the upstream sides of the first suction conveyance unit1 and the second suction conveyance unit 2 respectively, thepost-processing device is able to obtain the inspection results soonerthan a case where the inspection sections are located on the downstreamsides of the first and second suction conveyance units 1 and 2respectively and to execute necessary post-processing without delay.

Incidentally, the image inspection devices according to the ninth aspectto the eleventh aspect include not only the illustrated case where twosets of one suction conveyance unit and one inspection section arearrayed in mutually turned upside down postures along the inspectionobject conveyance direction but also a case where only one set of thesuction conveyance unit and the inspection section is installed. Thatis, in the illustrated image forming apparatus, also the imageinspection device from which the second suction conveyance unit 2 andthe second inspection section 12 are deleted so as to be configured onlyof the remaining first suction conveyance unit 1 and the remaining firstinspection section 11 is included in the image inspection devicesaccording to the ninth to eleventh aspects, and also the imageinspection device from which the first suction conveyance unit 1 and thefirst inspection unit 11 are deleted so as to be configured only of theremaining second suction conveyance unit 2 and the remaining secondinspection section 12 is included in the image inspection devicesaccording to the ninth to eleventh aspects. In this case, installationof the intermediate guide plate 15 is unnecessary. In this case, thesame effects as the above-described effects in the illustrated case areobtained.

DESCRIPTION OF REFERENCE SIGNS

-   1 . . . first suction conveyance unit as a first conveyance unit-   2 . . . second suction conveyance unit as a second conveyance unit-   11 . . . first inspection section-   12 . . . second inspection section-   11 a, 12 a . . . one inspection section (camera) for which a    relatively low arrangement accuracy is required in the inspection    sections of the suction conveyance unit-   11 b, 12 b . . . the other inspection section (CIS) for which a    relatively high arrangement accuracy is required in the inspection    sections of the suction conveyance unit-   21 . . . first support section-   22 . . . second support section-   35 . . . fixing pin which configures a conveyance direction    adjustment element of the suction conveyance unit-   36 . . . positioning hole which configures the conveyance direction    adjustment element of the suction conveyance unit-   37 . . . movable pin which configures the conveyance direction    adjustment element of the suction conveyance unit-   38 . . . operation member which configures the conveyance direction    adjustment element of the suction conveyance unit-   39 . . . slot which configures the conveyance direction adjustment    element of the suction conveyance unit-   40 . . . operation handle which configures the conveyance direction    adjustment element of the suction conveyance unit-   42 . . . hanging prevention member-   43 . . . skew correction roller-   50 . . . guide rail which configures a camera moving mechanism-   51 . . . moving body which configures the camera moving mechanism-   52 . . . stationary plate which configures the camera moving    mechanism-   54 . . . rotating mechanism section which configures the camera    moving mechanism-   55 . . . cable carrier which configures the camera moving mechanism-   200, 200 a to 200 g . . . image inspection device-   A, B, C . . . fulcrum which rotatably supports the support section    on a frame of the image inspection device-   X . . . inspection object width direction-   Y . . . inspection object conveyance direction-   Z . . . lens portion rotation direction by the rotating mechanism    section

The invention claimed is:
 1. An image inspection device comprising: afirst conveyor including a first conveyor belt, driven by a driveroller, and conveying a sheet-shaped conveyance object by contactingonly one side thereof, wherein the first conveyor conveys a sheet-shapedinspection object located on an upper surface of the first conveyorbelt; a second conveyor including a second conveyor belt, driven by adrive roller, conveying the sheet-shaped conveyance object by contactingonly one side thereof, wherein the second conveyor is arranged apartfrom and adjacent to the first conveyor along an inspection objectconveyance direction such that the first conveyor and the secondconveyor do not overlap each other in the inspection object conveyancedirection, and conveys the sheet-shaped inspection object located on alower surface of the second conveyor belt; a first inspector whichinspects an image on a front surface of the inspection object located onthe upper surface of the first conveyor belt of the first conveyor; anda second inspector which inspects an image on a back surface of theinspection object located on the lower surface of the second conveyorbelt of the second conveyor.
 2. The image inspection device according toclaim 1, wherein the first conveyor and the second conveyor are arrangedon an upstream side and a downstream side respectively along theinspection object conveyance direction, and the lower surface of thesecond conveyor belt has an angle which is inclined downward toward thedownstream side relative to the upper surface of the first conveyor beltfor stable conveyance of the inspection object.
 3. The image inspectiondevice according to claim 2, wherein the angle of the lower surface ofthe second conveyor belt which is inclined downward toward thedownstream side is set in accordance with image forming conditions whenthe image is formed on the inspection object by a printing device. 4.The image inspection device according to claim 1, further comprising: afirst support to which the first inspector is attached and which isrotatably supported on a frame of the image inspection device at threepoints and is positioned relative to the first conveyor; and a secondsupport to which the second inspector is attached and which is rotatablysupported on the frame of the image inspection device at three pointsand is positioned relative to the second conveyor.
 5. The imageinspection device according to claim 1, further comprising: a thirdinspector which is arranged at a position which is different from theposition of the first inspector along the inspection object conveyancedirection and inspects the image on the front surface of the inspectionobject; and a fourth inspector which is arranged at a position which isdifferent from the position of the second inspector along the inspectionobject conveyance direction and inspects the image on the back surfaceof the inspection object, wherein on the first conveyor, in the firstinspector and the third inspector, one inspector which is relativelyhigh in arrangement accuracy is arranged relatively on the downstreamside of the inspection object conveyance direction and the otherinspector is arranged relatively on the upstream side of the inspectionobject conveyance direction, and on the second conveyor, in the secondinspector and the fourth inspector, one inspector which is relativelyhigh in arrangement accuracy is arranged relatively on the downstreamside of the inspection object conveyance direction and the otherinspector is arranged relatively on the upstream side of the inspectionobject conveyance direction.
 6. The image inspection device according toclaim 1, further comprising: a third inspector which is arrangeddownstream of the first inspector along the inspection object conveyancedirection and inspects the image on the front surface of the inspectionobject located on the upper surface of the first conveyor belt; and afourth inspector which is arranged downstream of the second inspectoralong the inspection object conveyance direction and inspects the imageon the back surface of the inspection object located on the lowersurface of the second conveyor belt, wherein the first inspectorinspects the image in a first linear inspection region on the frontsurface of the inspection object, the first linear inspection regionextending in a direction perpendicular to the inspection objectconveyance direction and extending in a plane parallel with the uppersurface of the first conveyor belt, and the third inspector inspects theimage in a first planar inspection region on the front surface of theinspection object, the first planar inspecting region extending in theplane parallel with the upper surface of the conveyor belt and beinglocated downstream of the first linear inspection region, and the secondinspector inspects the image in a second linear inspection region on theback surface of the inspection object, the second linear inspectionregion extending in a direction perpendicular to the inspection objectconveyance direction and extending in a plane parallel with the lowersurface of the second conveyor belt, and the fourth inspector inspectsthe image in a second planar inspection region on the back surface ofthe inspection object, the second planar inspection region extending inthe plane parallel with the lower surface of the second conveyor beltand being located downstream of the second linear inspection region. 7.The image inspection device according to claim 6, wherein the thirdinspector is movable in a direction which is parallel with the firstlinear inspection region, and the fourth inspector is movable in adirection which is parallel with the second linear inspection region. 8.The image inspection device according to claim 1, wherein on at leastone of the first conveyor and the second conveyor, at least one of thefirst inspector and the second inspector is installed on at least eitheran upstream-side end or a downstream-side end of the inspection objectconveyance direction.
 9. The image inspection device according to claim8, wherein the at least one of the first inspector and the secondinspector is installed on the downstream-side end of at least one of thefirst conveyor and the second conveyor.
 10. The image inspection deviceaccording to claim 8, wherein the at least one of the first inspectorand the second inspector is installed on the upstream-side end of atleast one of the first conveyor and the second conveyor.
 11. The imageinspection device according to claim 1, wherein the first conveyor isprovided upstream of the second conveyor in the inspection objectconveyance direction, the first inspector is provided closer to anupstream end of the upper surface of the first conveyor belt than adownstream end of the upper surface of the first conveyor belt in theinspection object conveyance direction, and the second inspector isprovided closer to an upstream end of the lower surface of the secondconveyor belt than a downstream end of the lower surface of the secondconveyor belt in the inspection object conveyance direction.
 12. Theimage inspection device according to claim 1, wherein the first conveyoris provided upstream of the second conveyor in the inspection objectconveyance direction, the first inspector is provided closer to adownstream end of the upper surface of the first conveyor belt than anupstream end of the upper surface of the first conveyor belt in theinspection object conveyance direction, and the second inspector isprovided closer to a downstream end of the lower surface of the secondconveyor belt than an upstream end of the lower surface of the secondconveyor belt in the inspection object conveyance direction.
 13. Theimage inspection device according to claim 1, wherein the upper surfaceof the first conveyor belt and the lower surface of the second conveyorbelt are provided substantially at a same position in a heightdirection, which is perpendicular to the upper surface of the firstconveyor.
 14. The image inspection device according to claim 1, furthercomprising: a third inspector that is arranged downstream of the firstinspector along the inspection object conveyance direction and inspectsthe image on the front surface of the inspection object positioned onthe upper surface of the first conveyor belt, wherein an arrangementaccuracy of the third inspector is higher than an arrangement accuracyof the first inspector.
 15. The image inspection device according toclaim 1, further comprising: a fourth inspector that is arrangeddownstream of the second inspector along the inspection objectconveyance direction and inspects the image on the back surface of theinspection object positioned on the lower surface of the second conveyorbelt, wherein an arrangement accuracy of the fourth inspector is higherthan an arrangement accuracy of the second inspector.